Exposure to toxic agents, and especially CW agents, and related toxins, is a potential hazard to the armed forces and to civilian populations, since CW agents are stockpiled by several nations, and other nations and groups actively seek to acquire these materials. Some commonly known CW agents are bis-(2-chloroethyl) sulfide (HD or mustard gas), pinacolyl methylphosphonothiolate (GD) and 0-ethyl S-(2-diisopropylamino)ethyl methylphosphonothiolate (VX), as well as analogs and derivatives of these agents. These CW agents are generally delivered as fine aerosol mists which, aside from presenting an inhalation threat, will deposit on surfaces of military equipment and hardware, including uniforms, weapons, vehicles, vans and shelters. Once such equipment and hardware is contaminated with one of the previously mentioned highly toxic agents, the agent must be removed in order to minimize contact hazards.
For this reason, there is an acute need to develop and improve technology for decontamination of highly toxic materials. This is especially true for the class of toxic agents known as nerve agents or nerve gases which are produced and stockpiled for both industrial use and as CW agents. Simply by way of example, one class of nerve agents with a high level of potential lethality is the class that includes organophosphorus-based (“OP”) compounds, such as Sarin, Soman, and VX. Such agents can be absorbed through inhalation and/or through the skin of an animal or person. The organophosphorus-type (“OP”) CW materials typically manifest their lethal effects against animals and people by inhibiting acetylcholine esterase (“AChE”) enzyme at neuromuscular junctions between nerve endings and muscle tissue to produce an excessive buildup of the neurotransmitter acetylcholine, in an animal or person. This can result in paralysis and death in a short time.
In addition to the concerns about CW agents, there is also a growing need in industry for decontamination of industrial chemicals and/or insecticides, for example, ACHE-inhibiting pesticides such as parathion, paraoxon and malathion, among others. Thus, it is very important to be able to effectively detoxify a broad spectrum of toxic agents, including, but not limited to, organophosphorus-type compounds, from contaminated surfaces and sensitive equipment.
CW agents and related toxins are so hazardous that simulants have been developed for purposes of screening decontamination and control methods. These simulants are 2-chloroethylphenyl sulfide (CEPS), an HD simulant, dimethyl methyl phosphonate (DMMP), a G-agent simulant, and diphenylphosphonothioate (DPPT), a VX simulant.
Currently, the U.S. Army uses a nerve agent decontamination solution, DS2, which is composed (by weight) of 2% NaOH, 28% ethylene glycol monomethyl ether, and 70% diethylenetriamine (Richardson, G. A. “Development of a package decontamination system,” EACR-1 310-17, U.S. Army Edgewood Arsenal Contract Report (1972), incorporated by reference herein). Although this decontamination solution is effective against OP nerve agents, it is quite toxic, flammable, highly corrosive, and releases toxic by-products into the environment. For example, a component of DS2, namely methyl cellosolve, is a teratogen, so that the manufacture and use of DS2 also presents a potential health risk. DS2 protocol calls for waiting 30 minutes after DS2 application, then rinsing the treated area with water in order to complete the decontamination operation. The need to haul water to a site decontaminated by, DS2 is a further disadvantage for the use of DS2. Thus, there remains a need for an alternative decontamination technology that is both effective and non-hazardous to personnel, sensitive equipment, and/or the environment.
One decontamination material used as an alternative to DS2 is XE555 resin (Ambergard™ Rohm & Haas Company, Philadelphia, Pa.). XE555 is presently being used by the military for immediate decontamination applications. The objective of immediate decontamination operations is to remove toxic agents from the contaminated surface as rapidly as possible. However, XE555 has several disadvantages. Although effective at removing chemical agents, XE555 does not possesses sufficient reactive properties to neutralize the toxic agent(s) picked up by this resin. Thus, after use for decontamination purposes, XE555 itself presents an ongoing threat from off-gassing toxins and/or vapors mixed with the resin. In addition, XE555 is relatively expensive in the quantities required for decontamination purposes.
Bartram and Wagner (U.S. Pat. No. 5,689,038, incorporated by reference herein) report the use of an aluminum oxide and a mixture of aluminum oxide and magnesium monoperoxyphthalate (MMPP) to decontaminate surfaces contacted with droplets of CW agents.
This patent reports that both materials were able to effectively remove such toxic agents from a surface to the same extent as XE555. In addition, both materials represented improvements in CW agent degrading reactivity and in reducing off-gassing of toxins relative to XE555. However, it should be appreciated that the sorbents described by Bartram and Wagner were based on an activated aluminum oxide. Activated aluminum oxide is distinguishable from other forms of aluminum oxide in that it is a highly porous granular form of aluminum oxide which has a preferential capacity to adsorb moisture from gases, vapors or liquids. However, the Bartram and Wagner patent fails to describe methods to chemically optimize the aluminum oxide. Instead, the reported sorbents were based on pre-existing, commercially available materials, such as Selexsorb CD™, a product of the Alcoa Company. Essentially, Bartram and Wagner reported that their aluminum oxide is modified by size reduction, grinding or milling.
Thus, there remains a need in the art for even more effective, chemically modified forms of aluminum oxide, and for still further compositions and methods, to allow for the rapid and effective removal and/or decontamination of CW agents and related highly toxic materials in an environmentally acceptable and cost-effective process.